Manual motor starter combined with fused circuit protectors

ABSTRACT

A manual motor starter having interchangeable heaters for its overload sensing means is combined with fusible motor shortcircuit protectors (MSCPs) to achieve electrical coordination in which the MSCPs provide protection against severe fault conditions and the overload sensing means of the manual motor starter provides protection against running overloads. The MSCPs act on a common trip bar mounted to operate a crank engageable with the common trip bar of the starter for automatic opening of the starter contacts in the event an MSCP blows. Each MSCP is electrically wired in series with one pole of the starter in a circuit position between the contacts and the heater of the overload sensing means, so that the protector is not bypassed if heater burnout produces a phase-to-phase short.

United States Patent 9 1191 Di Marco et al.

1 51 Sept. 17, 1974 MANUAL MOTOR STARTER COMBINED WITH FUSED CIRCUITPROTECTORS [75'] Inventors: Bernard Di Marco, Bellefontaine,

Ohio; Frank W. Kussy, l-laverford, Pa.; John B. Cataldo, Moorestown,

[73] Assignee: I-T-E Imperial Corporation, Spring House, Pa.

[22] Filed: Mar. 1, 1973 {21] Appl. No.2 336,995

52 us. 01. 317/1311, 200/50 A 51 110.0. ..H02h 7/08 58 Fieldof'Search....,... 200/50 A; 317/1 1140 A,

A [56] References Cited UNITED'STATES PATENTS 2,191,523 2/1940 Ellis200/50 A 2,907,840 10/1959 Cole 200/50 A 2,919,328 12/1959 Kozacka317/40 A 2,920,164 l/l960 Edsall 317/40 A 2,920,241 l/l960 Jacobs, Jr.et al... 317/40 A 2,965,809 12/1960 Edsall 317/13 R 3,518,597 3,581,0325 1971 Christensen ..200/50A 6/1970 Platz et al. 337/46 Primary Examinerl. D. Miller Assistant ExaminerPatrick R. Salce Attorney, Agent, orFirmOstrolenk, Faber, Gerb &

' Soffen [5 7 ABSTRACT A manual motor starter having interchangeableheaters for its overload sensing means is combined with fusible motorshort-circuit protectors (MSCPs) to achieve electrical coordination inwhich the MSCPs provide protection against severe fault conditions andthe overload sensing means of the manual motor starter providesprotection against'r'unning overloads.

The MSCPs act on a common trip bar mounted to operate a crank engageablewith the common trip bar of the starter for automatic opening of thestarter contacts in the event an MSCP blows. Each MSCP is electricallywired in series with one pole of the starter in a circuit positionbetween the contacts and the heater of the overload sensing means, sothat the protectoris not bypassed if heater burnout produces aphase-to-phase short.

, 9 Claims, 13 Drawing Figures PAIENIEDSEP 1 ram sum 1 0F 6 FII'l'allnHL U T PATENTEU SEPII mu I SHEU 2 'UF 6 PAIENIEBsEP x 71924 saw 3 or 6MANUAL MOTOR STARTER COMBINED WITH FUSED CIRCUIT PROTECTORS Thisinvention relates to electrical protective apparatus in general and moreparticularly relates to a manual motor starter combined with fusiblemotor short-circuit achieve to chieve both electrical and mechanicalcoordination.

Copending U.S. patent application [D-439(MCO)] Ser. No. 248,859, filedMay I, 1972, by J. B. Cataldo and F. W. Kussy, for a Motor ProtectingMeans, assigned to the assignee of the instant invention, describes thecooperation of fusible motor short-circuit protectors with anelectromagnetic contactortype motor starter. In such an arrangement,operation of a single MSCP is effective to operate a switch in theenergizing circuit for the operating coil of the electromagneticcontactor causing the latter to open and deenergize the motor. i

For many motor starter applications, it is desirable to utilize a manualmotor starter rather than the relatively expensive electromagnetic typestarter. In accordance with the instant invention, a manual motorstarter is electrically and mechanically coordinated with motorshort-circuit protecting means. In particular, a multipole manual motorstarter and an individual MSCP for each pole of the starter are placedwithin an enclosure having an openable cover. Each MSCP is wired inseries circuit between the contacts of a single starter pole and theinterchangeable heater for this pole, with the contacts being at theline end of the starter and the heater being at the load end. With thiswiring arrangement, in the event a heater burns out and a phase-tophaseshort results, this short-circuit current will pass through the MSCPcausing blowing thereof and thereby prevent total destruction of theapparatus. A common trip bar is provided for actuation by pins ejectedfrom the MSCPs upon blowing thereof. This common trip bar is operativelyconnected by a crank to operate the latch release means ofthe startercontact operating mechanism whenever a single MSCP blows. The movablecontact carrier of the starter is positioned to cooperate with a pair oflevers to provide cover and switch interlocks. The cover interlocknormally prevents opening of the enclosure cover when the starter isclosed. This interlock is deflected to an inoperative position by thecontact carrier when the starter is opened. Defeater means operable fromoutside the enclosure are provided to permit opening ofthe enclosurecover when the switch is closed. The switch interlock prevents closingof the starter unless the cover is closed. With the cover open, theswitch interlock blocks closing movement of the contact carrier, andclosing of the enclosure cover deflects the switch interlock so that itis no longer in blocking relationship with respect to the contactcarrier.

Accordingly, a primary object of the instant inventionis to provide anovel construction for electrical protective apparatus adapted for motorstarting.

Another object is to provide a novel combination of a manual motorstarter and motor short-circuit protectors.

Still another object is to provide a combination of this type in whichthe MSCPs are connected in series with each pole of the manual motorstarter at a circuit position between the contacts and overload sensingmeans heater in each pole.

A further'object is to provide a combination of this type in whichblowing of a single MSCP results in mechanical movement for the latchrelease of the manual starter.

A still further object is to provide a combination of this type mountedwithin an enclosure and provided with cover and switch interlock means.

These objects as well as other objects of this invention will becomereadily apparent after reading the following description of theaccompanying drawings in which:

FIG. 1 is a plan view of electrical protective apparatus constructed inaccordance with teachings of the instant invention and including amanual motor starter in combination with fusible motor short-circuitprotectors.

FIG. 2 is an end view looking in the direction of arrows 2-2 of FIG. 1.

FIG. 3 is an enlarged plan view of the electrical elements of FIG. 1with the contact cover of the manual starter removed.

FIG. 4 is an end view looking inthe direction of ar rows 4-4 of FIG. 3,with the enclosure door partially open.

FIG. 5 is a fragmentary portion of the end view of FIG. 4 with theenclosure door in its closed position.

FIG. 6 is an enlarged plan view showing the defeater member actuated soas to release the cover interlock.

FIG. 7 is an exploded perspective showing the relation between theinterlock members mounted within the enclosure and those mounted to thecover.

FIG. 8 is a side elevation of the manual motor starter looking in thedirection of arrows 8-8 of FIG. 3.

FIG. 9 is a plan view showing the interaction between the common tripbar operated by the motor shortcircuit protectors and the common tripbar of the manual motor starter.

FIG. 10 is a front elevation of the motor starter trip bar.

FIG. 11 is an end view looking in the direction of arrows 11-11 of FIG.10.

FIG. 12 is a cross-section of the motor starter load terminal takenthrough line 12-12 of FIG. 3, looking in the direction of arrows 12-12.

FIG. 13 is a cross-section showing the motor starter connecting pointwhich receives leads extending from the short-circuit protector means.

FIG. 14 is an end view looking in the direction of arrows 14-14 of FIG.13, showing the motor starter terminal connecting the load end of anMSCP to the motor starter.

Now referring to the Figures. Combination motor starter 20 of FIG. 1includes pan-like enclosure 21 having openable cover 22 connected alongone side of enclosure 21 by hinge 23. Screw 24 is used to maintain cover22 closed against accidental opening thereof. Disposed withinenclosure21 and secured to back wall 26 thereof are manual motor starter25 and insulating slab 27. The latter supports three line end terminals28 and three load end terminals 29. Each terminal 28 mounts anindividual fuse clip 32, and each of the terminals 29 mounts anindividual fuse clip 33. Each pair of clips 32, 33 removably mounts anindividual one of the three MSCPs 30.

Manual motor starter 25 is, with slight modification, the same as thedevice described in US. Pat. No.

3,518,597, issued June 30, 1970, E. T. Platz et al., for a Manual MotorStarter. As will hereinafter be seen, each MSCP 30 is connectedelectrically to an individual pole of starter 25. Each protector 30 is afusible device .of the type described in detail in US patent application[CS-253] Ser. No. 98,423, filed Dec. 15, 1970. The procedure forselecting MSCPs 30 and the heaters 31 (FIG. 8) of motor starter 25 toachieve proper electrical coordination is set forth in detail in theaforesaid application Ser. No. 248,859.

Briefly, manual motor starter 25 includes springpowered mechanism 35 foroperating movable contact carrier 36 up and down with respect to FIG. 8,so as to simultaneously close and open, respectively, all poles ofstarter 25. The bridging contacts 37 in all three poles of starter 25are mounted to upward extensions of contact carrier 36 and are locatedtoward the line end of starter 25. Interchangeable heater 31 is locatednear the load end of starter 25 and forms part of an overload trip meansincluding U-shaped bimetal 38 which, upon being heated, deflects to theleft to pivot common trip bar 40 counterclockwise with respect to itslongitudinal pivot axis 41. This moves latch tip 42 extending from tripbar 40 downward to release latch 43 of operating mechanism 35, so thatthe latter opens starter 25 by moving contact carrier 36 upward therebyseparating bridging contact 37 from spaced stationary contacts 44, 45.

Common trip bar 51 at the load end of protectors 30 is pivotally mountedadjacent slat 27 by pivot assemblies 52. The construction of trip bar 51and mounting thereof are described in detail in the aforesaid copendingapplication Ser. No. 248,859. The three transverse extensions 53 of tripbar 51 are each positioned in alignment with the ejectable tripindicating pin 54 of a different MSCP 30. When pin 54 of any one of theMSCPs 30 is released and moves downward with respect to FIG. 3, thispivots trip bar 51 into engagement with car 56 of interconnecting crankor lever 55 that is pivotally mounted at 57 to integrally formed upwardextension 58 of insulating slab 27. The other end 59 of crank 55 (FIG.9) extends through starter housing opening 18 (FIG. 8) and is engageablewith extension 61. of manual starter trip bar 40. Spring 62 engagescrank 55 at a point between pivot 57 and end 59 so as to bias crank 55ina clockwise direction; Thus, ejection of a single protector pin 54operates common trip bar 51 which in turn pivots crank 55counterclockwise with respect to FIG. against the force exerted by thecrank biasing means 62, with crank tip 59 engaging trip bar 40 to pivotthe latter counterclockwise with respect to FIG. 8, thereby releasinglatch 43 that normally maintains contact operating mechanism 35 in areset condition.

For each pole of manual motor starter 25, the current path between itsline terminal 61 and its load terminal 62 proceeds from line sidestationary contact 45 through bridging contact 37 to load sidestationary contact 44 mounted on conducting strap 63, throughinsulation-covered wire 64 to the line end of a fusible protector 30,through protector 30 and insulatorcovered conductor 65 at the load endthereof to one leg of L-shaped connector 66 whose other leg supports oneend of U-shaped heater 31, and through heater 31 to load terminal 62.

For reasons of safety, starter 25 should not be operable to its closedposition unless enclosure cover 22 is closed, and cover 22 should beprevented from opening unless starter 25 is opened. Thus, device 20 isprovided with interlock assembly 70 positioned between starter 25 andinsulating slab 27. Assembly 70 includes bracket 71 secured by screws 72to common plate 91 mounted to rear wall 26 of enclosure 21. L-shapedinterlock levers 73, 74 are pivotally secured to bracket 71 by pin 75that extends between spaced legs 76, 77 of bracket 71 and through levers73, 74 at the junctions between the respective legs thereof. Levers 73,74 are positioned between arms 76, 77 and are spaced from each other byspacer 78. The free ends of the horizontal legs of levers 73, 74 areengaged respectively by coil springs 81, 82 which bias the vertical legsof levers 73, 74 toward the left side of movable contact carrier 36 whenviewed in FIGS. 4 and 5, thereby urging insulating projections 83, 84 onthe vertical legs of the respective levers 73, 74 through aperture 19 inthe side of the starter housing.

With the starter in its open position, contact carrier 36 is in itsraised position of FIG. 4 wherein insulating projection 83 of lever 73rests against the left side of contact carrier 36, and insulatingextension 84 of lever 74 is in blocking position below movable contactcarrier 36. Thus, lever projections 84 block downward movement ofcarrier 36 so that starter 25 cannot be closed.

The closing of enclosure cover 22 (FIG. 5) causes formation 79 ofZ-shaped bracket mounted to the inner surface of cover 22 to engage thesloping upper edge 85 of lever 74, thereby moving the lattercounterclockwise so that insulating extension 84 is moved to the left ofcontact carrier 36 and closing motion of the latter is no longerblocked.

Operation of contact carrier 36 downward to close starter 25 enablesinsulating projection 83 of lever 73 to move over the top of contactcarrier 36, thereby permitting clockwise movement of lever 73 so thathooklike formation 86 at the upper end of lever 73 moves into blockingrelationship above formation 87 of cover bracket 80, resulting ininterference between formations 86, 87 should an attempt be made to opencover 22 with starter 25 closed. The angular relationship between thelower edge of lever extension 83 and the upper surface of contactcarrier 36 is such that upward movement of contact carrier 36 causescover interlock lever 73 to pivot counterclockwise with respect to FIG.5 until formation 86 thereof moves to the left of bracket formation 87,thereby permitting cover 22 to be opened.

Should it become necessary to open cover 22 when starter 25 is closed,this may be accomplished by rotating defeater screw 88 clockwise withrespect to FIGS. 1 and 3 by using a screwdriver to operate the head ofscrew 88 positioned outside of cover 22. The lower end of screw 88 isjournaled within an aperture in bracket formation 87, and torsion spring92, interposed between disc 89 and the inside of cover 22, biases thehead of defeater screw 88 against the outer surface of cover 22 and alsobiases defeater 88 counterclockwise with respect to FIGS. 1 and 3.Defeater screw 88 carries eccentrically mounted disk 89 positionedbetween bracket formation 87 and cover 22. Disk 89 is keyed to screw 88so as to be rotated by rotation of screw 88. This causes disk 89 toengage formation 191 at the upper free end of lever 73, therebydeflecting lever 73 counterclockwise with respect to FIG. 5.

Electrical protective apparatus may be tripped remotely by utilizing asolenoid (not shown) to actuate trip bar 51 or other members 40 and 55of the mechanical trip system.

Even though the instant invention has been described in connection withmotor short-circuit protectors having very rapid rupturingcharacteristicsat short-circuit currents, it should be apparent to thoseskilled in the art that the term fused protector as used in thefollowing claims is broad enough to encompass any type of fuse that iscoordinated with the heater of the overload trip means.

Although in the foregoing preferred embodiments have been discussed,many variations and modifications will now become apparent to thoseskilled in the art, and it is therefore understood that this inventionis not limited by the disclosure but only by the appending claims.

The embodiments of the invention in which an exclusive privilege orproperty is claimed are defined as follows:

1. Electrical protective apparatus including an enclosure having anopenable cover, a multi-pole switch unit within said enclosure, afused'protector section within said enclosure, and first means withinsaid enclosure responsive to actuation of said section for causing saidswitch unit to open, first interlock means to normally prevent openingof said cover when said switching unit is closed, and second interlockmeans to normally prevent closing of said switch unit when said cover isopen; said switch unit having a load terminal for each pole thereof at aload end thereof and having a line terminal for each pole thereof at aline end thereof; a first and a second pole of said switch unitincluding separable contact means at said line end and overload sensingmeans, including heater means, at said load end; said fused protectorsection including first and second fuse protector portions; conductormeans electrically connecting said first portion between and in seriescircuit with the heater means and contact means of said first pole;conductor means electrically connecting said second portion between andin series circuit with the heater means and contact means of said secondpole; said switch unit including a mechanism for opening said contactmeans of all poles simultaneously, said mechanism having a latchablepart which when latched permits the contact means to be closed and whenreleased permits said mechanism to open said contact means; releasablelatch means for normally holding said part latched; a first trip baroperable by said overlaod sensing means, upon detecting overloadconditions, to release said latch means; said first means including asecond trip bar operable by said fused protector portions under faultconditions more severe than said overload conditions to operate thefirst trip bar and thereby release said latch means.

2. Electrical protective apparatus as set forth in claim 1 in which thefirst means also includes a pivoted member for transmitting motion ofthe second trip bar to said first trip bar.

3. Electrical protective apparatus as set forth in claim 1 in which theportions of the protector section are elongated and extend generallyparallel to each other and to the sides of the switch unit; said firstand second trip bars being generally parallel to each other; said secondtrip bar being at one end of the protector section near the load end ofthe switch unit.

- a first and a second pole of said switch unit including separablecontact means; each of the contact means including a movable contactmember; said switch unit also including a carrier to which the movablecontact members are mounted; said carrier being connected to saidmechanism for operation thereby from a first position wherein saidswitch unit is closed to a second position wherein said switch unit isopen; said first interlock means including a first interlock member andbiasing means exerting a force on said first interlock member urging ittoward said carrier to a locking position wherein the first interlockmember holds the cover closed, said carrier in operating from its saidsecond to said first position moving said first interlock member againstthe force of the biasing means to a releasing position wherein saidcover is no longer held by said first interlock member.

5. Electrical protective apparatus as set forth in claim 4 in which thesecond interlock means includes a second interlock member and biasingmeans exerting a biasing force on said second interlock member urging ittoward said carrier to a blocking position in which said secondinterlock member prevents operation of said carrier from its said secondto its said first position, said cover upon closing thereof operatingsaid second interlock member against the force of its said biasing meansto a non-blocking position wherein said carrier is operable to its saidfirst position.

6. Electrical protective apparatus as set forth in claim 5 in whichthere is a bracket secured to said cover on the inside thereof; saidbracket having a first formation to engage said second interlock memberto move same from said blocking to non-blocking position when said coveris moved to its closed position; said bracket also having a secondformation engaged by said first interlock member when the latter is insaid locking position to prevent opening of said cover,

7. Electrical protective apparatus as set forth in claim 6 alsoincluding defeater means operable from outside said cover to move thefirst interlock member to its releasing position when the cover isclosed; said bracket also having a formation to guide movement of saiddefeater means.

8. Electrical protective apparatus as set forth in claim 5 in which saidswitch unit includes a mechanism for opening said contact means of allpoles simultaneously, said mechanism having a latchable part which whenlatched permits the contact means to be closed and when released permitssaid mechanism to open said contact means; releasable latch means fornormally holding said part latched; a first trip bar operable by saidoverload sensing means, upon detecting overload conditions, to releasesaid latch means; a fused protector section within said enclosure, andfirst means within said enclosure responsive to actuation of saidsection for causing said switch unit to open; said switch unit alsohaving a load terminal for each pole thereof at a load end thereof andhaving a line terminal for each pole thereof at a line end thereof, andoverload sensing means, including heater means, at said load end; saidfused protector section including first and second fuse protectorportions; conductor means electrically connecting said first portionbetween and in series circuit with the heater means and contact means ofsaid first pole; conductor means electrically connecting said secondportion between and in series circuit with the heater meansifand contactmeans of said second pole; said first means including a second trip baroperable by said fused protector portions under fault conditions movesevere than said overload conditions to operate the first trip bar andthereby release said latch means.

tion near the load end of the switch unit.

1. Electrical protective apparatus including an enclosure having anopenable cover, a multi-pole switch unit within said enclosure, a fusedprotector section within said enclosure, and first means within saidenclosure responsive to actuation of said section for causing saidswitch unit to open, first interlock means to normally prevent openingof said cover when said switching unit is closed, and second interlockmeans to normally prevent closing of said switch unit when said cover isopen; said switch unit having a load terminal for each pole thereof at aload end thereof and having a line terminal for each pole thereof at aline end thereof; a first and a second pole of said switch unitincluding separable contact means at said line end and overload sensingmeans, including heater means, at said load end; said fused protectorsection including first and second fuse protector portions; conductormeans electrically connecting said first portion between and in seriescircuit with the heater means and contact means of said first pole;conductor means electrically connecting said second portion between andin series circuit with the heater means and contact means of said secondpole; said switch unit including a mechanism for opening said contactmeans of all poles simultaneously, said mechanism having a latchablepart which when latched permits the contact means to be closed and whenreleased permits said mechanism to open said contact means; releasablelatch means for normally holding said part latched; a first trip baroperable by said overlaod sensing means, upon detecting overloadconditions, to release said latch means; said first means including asecond trip bar operable by said fused protector portions under faultconditions more severe than said overload conditions to operate thefirst trip bar and thereby release said latch means.
 2. Electricalprotective apparatus as set forth in claim 1 in which the first meansalso includes a pivoted member for transmitting motion of the secondtrip bar to said first trip bar.
 3. Electrical protective apparatus asset forth in claim 1 in which the portions of the protector section areelongated and extend generally parallel to each other and to the sidesof the switch unit; said first and second trip bars being generallyparallel to each other; said second trip bar being at one end of theprotector section near the load end of the switch unit.
 4. Electricalprotective apparatus including an enclosure having an openable cover, amulti-pole switch unit within said enclosure, first interlock means tonormally prevent opening of said cover when said switching unit isclosed, and second interlock means to normally prevent closing of saidswitch unit when said cover is open; a first and a second pole of saidswitch unit including separable contact means; each of the contact meansincluding a movable contact member; said switch unit also including acarrier to which the movable contact members are mounted; said carrierbeing connected to said mechanism for operation thereby from a firstposition wherein said switch unit is closed to a second position whereinsaid switch unit is open; said first interlock means including a firstinterlock member and biasing means exerting a force on said firstinterlock member urging it toward said carrier to a locking positionwherein the first interlock member holds the cover closed, said carrierin operating from its said second to said first position moving saidfirst interlock member against the force of the biasing means to areleasing position wherEin said cover is no longer held by said firstinterlock member.
 5. Electrical protective apparatus as set forth inclaim 4 in which the second interlock means includes a second interlockmember and biasing means exerting a biasing force on said secondinterlock member urging it toward said carrier to a blocking position inwhich said second interlock member prevents operation of said carrierfrom its said second to its said first position, said cover upon closingthereof operating said second interlock member against the force of itssaid biasing means to a non-blocking position wherein said carrier isoperable to its said first position.
 6. Electrical protective apparatusas set forth in claim 5 in which there is a bracket secured to saidcover on the inside thereof; said bracket having a first formation toengage said second interlock member to move same from said blocking tonon-blocking position when said cover is moved to its closed position;said bracket also having a second formation engaged by said firstinterlock member when the latter is in said locking position to preventopening of said cover.
 7. Electrical protective apparatus as set forthin claim 6 also including defeater means operable from outside saidcover to move the first interlock member to its releasing position whenthe cover is closed; said bracket also having a formation to guidemovement of said defeater means.
 8. Electrical protective apparatus asset forth in claim 5 in which said switch unit includes a mechanism foropening said contact means of all poles simultaneously, said mechanismhaving a latchable part which when latched permits the contact means tobe closed and when released permits said mechanism to open said contactmeans; releasable latch means for normally holding said part latched; afirst trip bar operable by said overload sensing means, upon detectingoverload conditions, to release said latch means; a fused protectorsection within said enclosure, and first means within said enclosureresponsive to actuation of said section for causing said switch unit toopen; said switch unit also having a load terminal for each pole thereofat a load end thereof and having a line terminal for each pole thereofat a line end thereof, and overload sensing means, including heatermeans, at said load end; said fused protector section including firstand second fuse protector portions; conductor means electricallyconnecting said first portion between and in series circuit with theheater means and contact means of said first pole; conductor meanselectrically connecting said second portion between and in seriescircuit with the heater means and contact means of said second pole;said first means including a second trip bar operable by said fusedprotector portions under fault conditions move severe than said overloadconditions to operate the first trip bar and thereby release said latchmeans.
 9. Electrical protective apparatus as set forth in claim 8 inwhich the portions of the protector section are elongated and extendgenerally parallel to each other and to the sides of the switch unit;said first and second trip bars being generally parallel to each other;said second trip bar being at one end of the protector section near theload end of the switch unit.